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PHILADELPHIA (CBS) — An old scam is making its way around Facebook again this holiday season.

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Dubbed the “Secret Sister” scam, it starts with a post asking a user to buy a gift worth $10 or more and to add your name to the list.

In exchange, the user is promised 36 gifts through the mail in return.

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Instead, users are scammed out of their money, while making their personal information public in the process.

The scam has been around since 2015, according to Snopes, and pops up every holiday season.

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It’s also illegal, according to the U.S. Postal Service, because these chain letters are a form of gambling.